技术领域technical field
本发明涉及显示技术领域，具体涉及一种显示基板及其制备方法、显示装置。The invention relates to the field of display technology, in particular to a display substrate, a preparation method thereof, and a display device.
背景技术Background technique
随着显示技术的发展，液晶显示装置(Liquid Crystal Display，LCD)因具有高画质、省电、机身薄及应用范围广等优点，被广泛的应用于手机、电视、个人数字助理、数字相机、笔记本电脑、台式计算机等各种消费性电子产品，成为显示装置中的主流。近年来，有机发光二极管显示装置(Organic Light Emitting Diode，OLED)作为一种新兴的平板显示装置，因具有自发光、驱动电压低、发光效率高、响应时间短、清晰度和对比度高、近180°视角、使用温度范围宽、更为轻薄、可实现柔性显示和大面积全色显示等优点，在目前的显示市场中受到了更为广泛的关注，被业界公认为是最有发展潜力的显示装置。目前，小尺寸电子设备中已开始采用柔性OLED显示装置。With the development of display technology, liquid crystal display devices (Liquid Crystal Display, LCD) are widely used in mobile phones, televisions, personal digital assistants, digital Various consumer electronic products such as cameras, notebook computers, and desktop computers have become the mainstream of display devices. In recent years, Organic Light Emitting Diode (OLED), as an emerging flat-panel display device, has self-illumination, low driving voltage, high luminous efficiency, short response time, high definition and contrast, nearly 180 ° viewing angle, wide operating temperature range, lighter and thinner, flexible display and large-area full-color display, etc., have attracted more attention in the current display market, and are recognized by the industry as the display with the most development potential. device. Currently, flexible OLED display devices have begun to be used in small-sized electronic devices.
经本申请发明人研究发现，现有柔性OLED显示装置在弯曲过程中，存在发光不稳定的问题。The inventors of the present application found that the existing flexible OLED display device has the problem of unstable light emission during the bending process.
发明内容Contents of the invention
本发明实施例所要解决的技术问题是，提供一种显示基板及其制备方法、显示装置，以解决现有显示装置存在的发光不稳定的问题。The technical problem to be solved by the embodiments of the present invention is to provide a display substrate, a manufacturing method thereof, and a display device, so as to solve the problem of unstable luminescence existing in the existing display devices.
为了解决上述技术问题，本发明实施例提供了一种显示基板，包括柔性基底以及设置在所述柔性基底上的薄膜晶体管，所述柔性基底上嵌设有强化层，所述强化层的位置与薄膜晶体管沟道区的位置相对应，用于提高薄膜晶体管沟道区的抗形变能力。In order to solve the above technical problems, an embodiment of the present invention provides a display substrate, including a flexible substrate and a thin film transistor disposed on the flexible substrate, a reinforcement layer is embedded on the flexible substrate, and the location of the reinforcement layer is the same as The positions of the channel regions of the thin film transistors are corresponding to improve the deformation resistance of the channel regions of the thin film transistors.
可选地，所述柔性基底上开设有凹槽，所述凹槽的深度为所述柔性基底厚度的30％～50％，所述强化层嵌设在所述凹槽内，所述强化层的表面与所述柔性基底的表面平齐。Optionally, a groove is opened on the flexible substrate, the depth of the groove is 30% to 50% of the thickness of the flexible substrate, the reinforcing layer is embedded in the groove, and the reinforcing layer The surface is flush with the surface of the flexible substrate.
可选地，所述强化层在所述柔性基底上的正投影包含所述薄膜晶体管的有源层在所述柔性基底上的正投影。Optionally, the orthographic projection of the strengthening layer on the flexible substrate includes the orthographic projection of the active layer of the thin film transistor on the flexible substrate.
可选地，所述柔性基底的材料包括聚酰亚胺，所述强化层的材料包括氧化石墨烯/聚酰亚胺复合薄膜或改性氧化石墨烯/聚酰亚胺复合薄膜。Optionally, the material of the flexible substrate includes polyimide, and the material of the strengthening layer includes a graphene oxide/polyimide composite film or a modified graphene oxide/polyimide composite film.
可选地，所述氧化石墨烯/聚酰亚胺复合薄膜中，所述氧化石墨烯的质量分数为3％～7％；所述改性氧化石墨烯/聚酰亚胺复合薄膜中，所述改性氧化石墨烯的质量分数为0.5％～1.5％。Optionally, in the graphene oxide/polyimide composite film, the mass fraction of the graphene oxide is 3% to 7%; in the modified graphene oxide/polyimide composite film, the The mass fraction of the modified graphene oxide is 0.5%-1.5%.
可选地，所述薄膜晶体管包括低温多晶硅薄膜晶体管。Optionally, the thin film transistor includes a low temperature polysilicon thin film transistor.
本发明实施例还提供了一种显示装置，包括前述的显示基板。An embodiment of the present invention also provides a display device, including the aforementioned display substrate.
为了解决上述技术问题，本发明实施例还提供了一种显示基板的制备方法，其特征在于，包括：In order to solve the above technical problems, an embodiment of the present invention also provides a method for preparing a display substrate, which is characterized in that it includes:
形成嵌设有强化层的柔性基底；forming a flexible substrate embedded with a strengthening layer;
在所述柔性基底上形成薄膜晶体管，使所述强化层的位置与薄膜晶体管沟道区的位置相对应，以提高薄膜晶体管沟道区的抗形变能力。A thin film transistor is formed on the flexible substrate, and the position of the strengthening layer corresponds to that of the channel region of the thin film transistor, so as to improve the deformation resistance of the channel region of the thin film transistor.
可选地，形成嵌设有强化层的柔性基底，包括：Optionally, forming a flexible substrate embedded with a strengthening layer comprising:
在玻璃载板上形成未完全交联的柔性薄膜；Formation of incompletely crosslinked flexible films on glass supports;
在所述未完全交联的柔性薄膜上开设凹槽，所述凹槽的深度为所述未完全交联的柔性薄膜厚度的30％～50％；Opening grooves on the incompletely crosslinked flexible film, the depth of the grooves being 30% to 50% of the thickness of the incompletely crosslinked flexible film;
在所述凹槽内形成未完全交联的强化薄膜，所述未完全交联的强化薄膜的表面与所述未完全交联的柔性薄膜的表面平齐；forming an incompletely crosslinked reinforced film in the groove, the surface of the incompletely crosslinked reinforced film is flush with the surface of the incompletely crosslinked flexible film;
通过固化处理，使所述未完全交联的柔性薄膜和未完全交联的强化薄膜完全交联，形成嵌设有强化层的柔性基底，且强化层与柔性基底融为一体。Through the curing treatment, the incompletely crosslinked flexible film and the incompletely crosslinked reinforced film are completely crosslinked to form a flexible substrate embedded with a reinforced layer, and the reinforced layer is integrated with the flexible substrate.
可选地，所述未完全交联的柔性薄膜包括交联程度为50％-80％的聚酰亚胺薄膜，所述未完全交联的强化薄膜包括交联程度为50％-80％的氧化石墨烯/聚酰亚胺复合薄膜或交联程度为50％-80％的改性氧化石墨烯/聚酰亚胺复合薄膜。Optionally, the incompletely cross-linked flexible film includes a polyimide film with a cross-linking degree of 50%-80%, and the incompletely cross-linked reinforced film includes a polyimide film with a cross-linking degree of 50%-80%. A graphene oxide/polyimide composite film or a modified graphene oxide/polyimide composite film with a crosslinking degree of 50%-80%.
可选地，所述氧化石墨烯/聚酰亚胺复合薄膜中，所述氧化石墨烯的质量分数为3％～7％；所述改性氧化石墨烯/聚酰亚胺复合薄膜中，所述改性氧化石墨烯的质量分数为0.5％～1.5％。Optionally, in the graphene oxide/polyimide composite film, the mass fraction of the graphene oxide is 3% to 7%; in the modified graphene oxide/polyimide composite film, the The mass fraction of the modified graphene oxide is 0.5%-1.5%.
可选地，所述固化处理包括：在200℃～350℃高温烘箱中恒温处理1.5小时～2.5小时。Optionally, the curing treatment includes: constant temperature treatment in a high-temperature oven at 200° C. to 350° C. for 1.5 hours to 2.5 hours.
可选地，Optionally,
在所述未完全交联的柔性薄膜上开设凹槽，包括：在所述未完全交联的柔性薄膜上涂覆一层负性光刻胶，通过曝光、显影形成负性光刻胶图案，采用干刻方式刻蚀未被负性光刻胶图案覆盖的所述未完全交联的柔性薄膜，在所述未完全交联的柔性薄膜上形成凹槽，所述凹槽的深度为所述未完全交联的柔性薄膜厚度的30％～50％；Opening grooves on the incompletely crosslinked flexible film includes: coating a layer of negative photoresist on the incompletely crosslinked flexible film, forming a negative photoresist pattern by exposing and developing, The incompletely crosslinked flexible film that is not covered by the negative photoresist pattern is etched by dry etching, and a groove is formed on the incompletely crosslinked flexible film, and the depth of the groove is the 30% to 50% of the thickness of the incompletely cross-linked flexible film;
在所述凹槽内形成未完全交联的强化薄膜，包括：涂覆氧化石墨烯/聚酰胺酸溶液或改性氧化石墨烯/聚酰胺酸溶液，形成未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜，所述未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜完全填充所述凹槽；采用化学机械平坦化工艺进行研磨，只保留所述凹槽中的未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜，在所述凹槽内形成未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜，所述未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜的表面与所述未完全交联的柔性薄膜的表面平齐。Forming an incompletely cross-linked reinforced film in the groove includes: coating graphene oxide/polyamic acid solution or modified graphene oxide/polyamic acid solution to form an incompletely cross-linked graphene oxide/polyamic acid solution. Imide composite film or incompletely crosslinked modified graphene oxide/polyimide composite film, the incompletely crosslinked graphene oxide/polyimide composite film or incompletely crosslinked modified oxidized The graphene/polyimide composite film completely fills the groove; the chemical mechanical planarization process is used to grind, and only the incompletely cross-linked graphene oxide/polyimide composite film or the uncrosslinked graphene oxide in the groove is kept. Fully cross-linked modified graphene oxide/polyimide composite film, forming incompletely cross-linked graphene oxide/polyimide composite film or incompletely cross-linked modified graphene oxide / polyimide composite film, the surface of the incompletely cross-linked graphene oxide/polyimide composite film or the modified graphene oxide/polyimide composite film of incomplete cross-linking and the incompletely cross-linked The surface of the cross-linked flexible film is even.
可选地，所述强化层在所述柔性基底上的正投影包含所述薄膜晶体管的有源层在所述柔性基底上的正投影。Optionally, the orthographic projection of the strengthening layer on the flexible substrate includes the orthographic projection of the active layer of the thin film transistor on the flexible substrate.
可选地，在所述柔性基底上形成薄膜晶体管，包括：在所述柔性基底上形成低温多晶硅薄膜晶体管。Optionally, forming a thin film transistor on the flexible substrate includes: forming a low temperature polysilicon thin film transistor on the flexible substrate.
本发明实施例提供了一种显示基板及其制备方法、显示装置，通过在基底上嵌设强化层，强化层与薄膜晶体管沟道区的位置相对应，提高了薄膜晶体管沟道区的抗形变能力，在显示基板弯曲时能够减小甚至消除薄膜晶体管沟道区的形变，避免因薄膜晶体管沟道区形变过大影响薄膜晶体管的电性参数，保证了发光稳定性，提升了显示品质，有效解决了现有显示装置存在的发光不稳定的问题。Embodiments of the present invention provide a display substrate, a preparation method thereof, and a display device. By embedding a strengthening layer on the substrate, the strengthening layer corresponds to the position of the channel region of the thin film transistor, thereby improving the deformation resistance of the channel region of the thin film transistor. ability, when the display substrate is bent, it can reduce or even eliminate the deformation of the channel region of the thin film transistor, avoid the electrical parameters of the thin film transistor due to excessive deformation of the channel region of the thin film transistor, ensure the stability of light emission, improve the display quality, and effectively The problem of unstable luminescence existing in the existing display device is solved.
当然，实施本发明的任一产品或方法并不一定需要同时达到以上所述的所有优点。本发明的其它特征和优点将在随后的说明书实施例中阐述，并且，部分地从说明书实施例中变得显而易见，或者通过实施本发明而了解。本发明实施例的目的和其它优点可通过在说明书、权利要求书以及附图中所特别指出的结构来实现和获得。Of course, implementing any product or method of the present invention does not necessarily need to achieve all the above-mentioned advantages at the same time. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the embodiments of the invention can be realized and obtained by the structures particularly pointed out in the description, claims as well as the appended drawings.
附图说明Description of drawings
附图用来提供对本发明技术方案的进一步理解，并且构成说明书的一部分，与本申请的实施例一起用于解释本发明的技术方案，并不构成对本发明技术方案的限制。附图中各部件的形状和大小不反映真实比例，目的只是示意说明本发明内容。The accompanying drawings are used to provide a further understanding of the technical solution of the present invention, and constitute a part of the description, and are used together with the embodiments of the application to explain the technical solution of the present invention, and do not constitute a limitation to the technical solution of the present invention. The shapes and sizes of the components in the drawings do not reflect the real scale, but are only intended to schematically illustrate the content of the present invention.
图1为本发明实施例显示基板的结构示意图；FIG. 1 is a schematic structural view of a display substrate according to an embodiment of the present invention;
图2为本发明实施例形成未完全交联的柔性薄膜图案后的示意图；2 is a schematic diagram of an incompletely crosslinked flexible film pattern formed in an embodiment of the present invention;
图3为聚酰亚胺在不同固化温度下的XRD图谱；Fig. 3 is the XRD spectrum of polyimide at different curing temperatures;
图4为本发明实施例形成光刻胶图案后的示意图；FIG. 4 is a schematic diagram after forming a photoresist pattern according to an embodiment of the present invention;
图5为本发明实施例刻蚀柔性薄膜后的示意图；Fig. 5 is a schematic diagram of an embodiment of the present invention after etching a flexible film;
图6为本发明实施例形成形成GO/PI或iGO/PI复合薄膜后的示意图；Figure 6 is a schematic diagram of the embodiment of the present invention after forming a GO/PI or iGO/PI composite film;
图7为本发明实施例研磨处理后的示意图；Fig. 7 is the schematic diagram after grinding treatment of the embodiment of the present invention;
图8为本发明实施例制备包括薄膜晶体管的阵列结构层后的示意图。FIG. 8 is a schematic diagram of an embodiment of the present invention after preparing an array structure layer including thin film transistors.
附图标记说明:Explanation of reference signs:
1—玻璃载板； 10—柔性基底； 10a—凹槽；1—glass carrier; 10—flexible substrate; 10a—groove;
11—缓冲层； 12—有源层； 13—第一绝缘层；11—buffer layer; 12—active layer; 13—first insulating layer;
14—栅电极； 15—第二绝缘层； 16—源电极；14—gate electrode; 15—second insulating layer; 16—source electrode;
17—漏电极； 18—第三绝缘层； 20—加强层；17—drain electrode; 18—third insulating layer; 20—strengthening layer;
100—光刻胶.100—photoresist.
具体实施方式Detailed ways
下面结合附图和实施例对本发明的具体实施方式作进一步详细描述。以下实施例用于说明本发明，但不用来限制本发明的范围。需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互任意组合。The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.
经本申请发明人研究发现，现有柔性OLED显示装置存在的发光不稳定问题，是弯曲过程导致薄膜晶体管沟道区变形造成的。目前，柔性OLED显示装置的薄膜晶体管(ThinFilm Transistor Array，TFT)通常采用低温多晶硅(Low Temperature Polysilicon，LTPS)薄膜晶体管。LTPS薄膜晶体管具有多方面的优势，电子迁移率可以达到200cm2/V-sec以上，不仅可有效减小薄膜晶体管的面积，提高开口率，而且可以在提高显示亮度的同时降低整体功耗，能够满足OLED显示装置电流型驱动的要求，但由于低温多晶硅LTPS属于无机半导体材料，柔性OLED显示装置的多次弯曲会造成低温多晶硅LTPS变形，进而造成薄膜晶体管沟道区发生形变，而薄膜晶体管沟道区的形变会影响薄膜晶体管的电性参数，如阈值电压和漏电流等，影响其驱动发光，从而出现发光不稳定的问题。经本申请发明人进一步研究发现，虽然采用有机薄膜晶体管(Organic Thin Film Transistor，OTFT)可以利用其窄沟道的特点减小沟道区形变，但由于OTFT载流子迁移率较低，为获得能够驱动OLED像素的电流，需要尽量缩短OTFT的沟道长度，而制备窄沟道需要高分辨率曝光设备，会极大地增加生产成本。The inventors of the present application found that the problem of unstable light emission in the existing flexible OLED display device is caused by the deformation of the channel region of the thin film transistor caused by the bending process. Currently, low temperature polysilicon (Low Temperature Polysilicon, LTPS) thin film transistors are generally used as thin film transistors (ThinFilm Transistor Array, TFT) of flexible OLED display devices. LTPS thin film transistors have many advantages. The electron mobility can reach more than 200cm2 /V-sec. It can not only effectively reduce the area of thin film transistors, increase the aperture ratio, but also reduce the overall power consumption while improving the display brightness. It meets the current driving requirements of OLED display devices, but because low-temperature polysilicon LTPS is an inorganic semiconductor material, repeated bending of flexible OLED display devices will cause deformation of low-temperature polysilicon LTPS, which in turn will cause deformation of the channel region of the thin film transistor, and the channel of the thin film transistor The deformation of the region will affect the electrical parameters of the thin film transistor, such as threshold voltage and leakage current, etc., which will affect its drive to emit light, thus causing the problem of unstable light emission. After further research by the inventors of the present application, it was found that although the use of an organic thin film transistor (Organic Thin Film Transistor, OTFT) can take advantage of its narrow channel characteristics to reduce the deformation of the channel region, due to the low carrier mobility of the OTFT, in order to obtain To be able to drive the current of OLED pixels, the channel length of OTFT needs to be shortened as much as possible, and the preparation of narrow channels requires high-resolution exposure equipment, which will greatly increase production costs.
为了解决现有OLED显示装置存在的发光不稳定的问题，本发明实施例提供了一种显示基板，显示基板包括基底以及设置在所述基底上的薄膜晶体管，所述基底上嵌设有强化层，所述强化层的位置与薄膜晶体管沟道区的位置相对应，用于提高薄膜晶体管沟道区的抗形变能力。In order to solve the problem of unstable luminescence existing in the existing OLED display device, an embodiment of the present invention provides a display substrate, the display substrate includes a substrate and a thin film transistor disposed on the substrate, and a strengthening layer is embedded on the substrate , the position of the strengthening layer corresponds to the position of the channel region of the thin film transistor, and is used to improve the deformation resistance of the channel region of the thin film transistor.
本发明实施例所提供的显示基板，通过在基底上嵌设强化层，强化层与薄膜晶体管沟道区的位置相对应，提高了薄膜晶体管沟道区的抗形变能力，在显示基板弯曲时能够减小甚至消除薄膜晶体管沟道区的形变，避免因薄膜晶体管沟道区形变过大影响薄膜晶体管的电性参数，保证了发光稳定性，提升了显示品质，有效解决了现有显示装置存在的发光不稳定的问题。In the display substrate provided by the embodiment of the present invention, by embedding a strengthening layer on the base, the strengthening layer corresponds to the position of the channel region of the thin film transistor, which improves the deformation resistance of the channel region of the thin film transistor, and can be bent when the display substrate is bent. Reduce or even eliminate the deformation of the channel region of the thin film transistor, avoid the influence of the electrical parameters of the thin film transistor due to excessive deformation of the channel region of the thin film transistor, ensure the stability of light emission, improve the display quality, and effectively solve the problems existing in the existing display device. Luminous instability issue.
下面通过具体实施例详细说明本发明实施例的技术方案。The technical solutions of the embodiments of the present invention will be described in detail below through specific examples.
第一实施例first embodiment
图1为本发明实施例显示基板的结构示意图。如图1所示，本实施例显示基板的主体结构包括柔性基底10、设置在柔性基底10上的缓冲层11以及设置在缓冲层11上的阵列结构层，阵列结构层包括多个薄膜晶体管，图1仅示意了一个薄膜晶体管。其中，薄膜晶体管包括有源层12、栅电极14、源电极16和漏电极17。本实施例显示基板还包括加强层20，在垂直于柔性基底10的平面内，加强层20嵌设在柔性基底10内，加强层20的表面与柔性基底10的表面平齐。在平行于柔性基底10的平面内，加强层20的位置与薄膜晶体管的有源层12的位置相对应，且加强层20在柔性基底上的正投影包含有源层12在柔性基底上的正投影。FIG. 1 is a schematic structural diagram of a display substrate according to an embodiment of the present invention. As shown in FIG. 1 , the main structure of the display substrate in this embodiment includes a flexible substrate 10, a buffer layer 11 disposed on the flexible substrate 10, and an array structure layer disposed on the buffer layer 11. The array structure layer includes a plurality of thin film transistors, FIG. 1 illustrates only one thin film transistor. Wherein, the thin film transistor includes an active layer 12 , a gate electrode 14 , a source electrode 16 and a drain electrode 17 . In this embodiment, the substrate further includes a reinforcement layer 20 , which is embedded in the flexible substrate 10 in a plane perpendicular to the flexible substrate 10 , and the surface of the reinforcement layer 20 is flush with the surface of the flexible substrate 10 . In a plane parallel to the flexible substrate 10, the position of the reinforcement layer 20 corresponds to the position of the active layer 12 of the thin film transistor, and the orthographic projection of the reinforcement layer 20 on the flexible substrate includes the orthographic projection of the active layer 12 on the flexible substrate. projection.
具体地，本实施例显示基板包括：柔性基底10，嵌设在柔性基底10内的加强层20，覆盖柔性基底10和加强层20的缓冲层11，设置在缓冲层11上的有源层12，覆盖有源层12的第一绝缘层13，设置在第一绝缘层13上的栅电极14，覆盖栅电极14的第二绝缘层15，其上开设有暴露出有源层12的两个第一过孔，设置在第二绝缘层15上的源电极16和漏电极17，源电极16和漏电极17分别通过第二绝缘层15上开设的两个第一过孔与有源层12连接，覆盖源电极16和漏电极17的第三绝缘层18，其上开设有暴露出漏电极17的第二过孔。通常，第一绝缘层13也称之为栅绝缘层(GI)，第二绝缘层15也称之为层间绝缘层(ILD)，第三绝缘层18也称之为钝化层(PVD)。本实施例中，第一绝缘层13、第二绝缘层15和第三绝缘层18的材料可以采用硅氧化物(SiOx)、硅氮化物(SiNx)、氮氧化硅(SiON)或上述材料的组合等，可采用单层、双层、多层或复合层等组合形式。栅电极14、源电极16和漏电极17的材料可以采用钼Mo、铝Al、金Au、钛Ti、铂Pt，钌Ru、铱Ir等金属以及它们的合金。柔性基底10的材料包括聚酰亚胺(PI)、聚对苯二甲酸乙二酯(PET)等聚合物材料。加强层20的材料包括氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜或改性氧化石墨烯/聚酰亚胺(iGO/PI)复合薄膜，加强层20的厚度为柔性基底10厚度的30％～50％。优选地，柔性基底10的材料采用聚酰亚胺(PI)，加强层20的厚度为柔性基底10厚度的50％。Specifically, the present embodiment shows that the substrate includes: a flexible substrate 10, a reinforcement layer 20 embedded in the flexible substrate 10, a buffer layer 11 covering the flexible substrate 10 and the reinforcement layer 20, and an active layer 12 disposed on the buffer layer 11. , the first insulating layer 13 covering the active layer 12, the gate electrode 14 arranged on the first insulating layer 13, the second insulating layer 15 covering the gate electrode 14, and two holes exposing the active layer 12 are opened on it. The first via hole, the source electrode 16 and the drain electrode 17 arranged on the second insulating layer 15, the source electrode 16 and the drain electrode 17 pass through the two first via holes opened on the second insulating layer 15 and the active layer 12 respectively. connected to the third insulating layer 18 covering the source electrode 16 and the drain electrode 17 , and a second via hole exposing the drain electrode 17 is opened thereon. Generally, the first insulating layer 13 is also called a gate insulating layer (GI), the second insulating layer 15 is also called an interlayer insulating layer (ILD), and the third insulating layer 18 is also called a passivation layer (PVD). . In this embodiment, the materials of the first insulating layer 13, the second insulating layer 15 and the third insulating layer 18 can be silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON) or the above materials. Combinations, etc., can be combined in the form of single-layer, double-layer, multi-layer or composite layers. The materials of the gate electrode 14, the source electrode 16 and the drain electrode 17 can be metals such as molybdenum Mo, aluminum Al, gold Au, titanium Ti, platinum Pt, ruthenium Ru, iridium Ir and their alloys. The material of the flexible substrate 10 includes polyimide (PI), polyethylene terephthalate (PET) and other polymer materials. The material of the reinforcement layer 20 includes graphene oxide/polyimide (GO/PI) composite film or modified graphene oxide/polyimide (iGO/PI) composite film, and the thickness of the reinforcement layer 20 is the thickness of the flexible substrate 10 30% to 50% of that. Preferably, the material of the flexible base 10 is polyimide (PI), and the thickness of the reinforcing layer 20 is 50% of the thickness of the flexible base 10 .
聚酰亚胺(PI)具有优异的热性能、化学稳定性、介电能力和力学性能，可以应用于航空航天、机械电子等领域，是应用较为广泛的高性能聚合物之一。一直以来，研究人员在碳材料改性聚酰亚胺方面作出了很多努力，以期望获得更好的热性能和力学性能，如采用碳纳米管和碳纤维改性聚酰亚胺，可提升复合材料的热稳定性和耐腐蚀性等。石墨烯的出现为碳材料改性聚酰亚胺提供了新的途径，研究表明，采用石墨烯改性聚酰亚胺可使复合材料的力学性能、电性能、耐热性能得到提升。研究表明，由于经异氰酸酯修饰后的石墨烯片层上有长的烷基长链，这些有机烷基长链在石墨烯的无机片层和聚酰亚胺的有机长链中起到了相容剂的作用，因而减少了石墨烯片层与聚酰亚胺基体结合部的应力缺陷，使得添加有特定含量的氧化石墨烯GO或改性氧化石墨烯iGO的聚酰亚胺薄膜的弹性模量会有显著的增加，而添加改性氧化石墨烯iGO相对于添加氧化石墨烯GO在整体上弹性模量的增加更显著。其中，弹性模量是应力和应变的比值，弹性模量越低，变形相对越大，刚度越小，材料易发生变形柔性越好；弹性模量越高，材料发生形变相对越小，刚度越大，即材料不易变形。已有的研究给出了氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜或改性氧化石墨烯/聚酰亚胺(iGO/PI)复合薄膜的力学性能，如表1所示。Polyimide (PI) has excellent thermal properties, chemical stability, dielectric properties and mechanical properties, and can be used in aerospace, mechatronics and other fields, and is one of the most widely used high-performance polymers. For a long time, researchers have made a lot of efforts in modifying polyimide with carbon materials in order to obtain better thermal and mechanical properties. For example, using carbon nanotubes and carbon fibers to modify polyimide can improve composite materials. thermal stability and corrosion resistance, etc. The emergence of graphene provides a new way for carbon materials to modify polyimide. Studies have shown that the use of graphene-modified polyimide can improve the mechanical properties, electrical properties, and heat resistance of composite materials. Studies have shown that due to the long alkyl chains on the isocyanate-modified graphene sheets, these organic alkyl chains act as compatibilizers in the inorganic sheets of graphene and the organic long chains of polyimide. Therefore, the stress defect at the joint between the graphene sheet and the polyimide matrix is reduced, so that the elastic modulus of the polyimide film with a specific content of graphene oxide GO or modified graphene oxide iGO will be reduced. There is a significant increase, and the overall increase in elastic modulus is more pronounced with the addition of modified graphene oxide iGO relative to the addition of graphene oxide GO. Among them, the elastic modulus is the ratio of stress to strain. The lower the elastic modulus, the larger the deformation, the smaller the stiffness, and the better the flexibility of the material. The higher the elastic modulus, the smaller the deformation of the material and the higher the stiffness. Large, that is, the material is not easily deformed. Existing studies have given the mechanical properties of graphene oxide/polyimide (GO/PI) composite films or modified graphene oxide/polyimide (iGO/PI) composite films, as shown in Table 1.
表1：GO/PI复合薄膜和iGO/PI复合薄膜的力学性能Table 1: Mechanical properties of GO/PI composite films and iGO/PI composite films
目前，已经有比较成熟的成膜技术制备氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜或改性氧化石墨烯/聚酰亚胺(iGO/PI)复合薄膜。例如，制备氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜包括：称取一定量干燥后的氧化石墨烯GO溶于二甲基乙酰胺(Dimethylacetamide，DMAc)中，超声2小时得到GO的DMAc溶液。将一定比例的GO的DMAc溶液与固含量为15wt％的聚酰胺酸(polyamide acid，PAA)溶液及DMAc溶剂混合搅拌4小时后，得到不同浓度的GO/PAA。将以上制备的GO/PAA溶液涂敷在玻璃载板上，置于70℃烘箱中抽真空加热10小时，得到GO/PAA的复合薄膜。将复合薄膜置于高温烘箱中，在100℃、200℃、300℃下分别恒温处理1小时(即阶梯式固化、热酰胺化)，即可得到氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜。利用同样的方法，也可以制备改性氧化石墨烯/聚酰亚胺(iGO/PI)复合薄膜。At present, there are relatively mature film-forming technologies to prepare graphene oxide/polyimide (GO/PI) composite films or modified graphene oxide/polyimide (iGO/PI) composite films. For example, the preparation of graphene oxide/polyimide (GO/PI) composite film includes: weighing a certain amount of dried graphene oxide GO and dissolving it in dimethylacetamide (Dimethylacetamide, DMAc), and ultrasonicating for 2 hours to obtain GO DMAc solution. After mixing a certain proportion of GO in DMAc solution with a solid content of 15wt% polyamic acid (PAA) solution and DMAc solvent and stirring for 4 hours, different concentrations of GO/PAA were obtained. The GO/PAA solution prepared above was coated on a glass carrier, placed in a 70 °C oven and heated under vacuum for 10 hours to obtain a composite film of GO/PAA. The composite film was placed in a high-temperature oven, and treated at a constant temperature of 100 °C, 200 °C, and 300 °C for 1 hour (ie, stepwise curing, thermal amidation), and the graphene oxide/polyimide (GO/PI ) Composite film. Using the same method, modified graphene oxide/polyimide (iGO/PI) composite films can also be prepared.
目前，制备改性氧化石墨烯已有成熟的工艺。例如，制备过程包括：把预先干燥过的GO(300mg)、十八烷基异氰酸酯(3.5g)和30ml的二甲基甲酰胺(DMF)置于100ml的烧瓶中，在氮气保护下超声混合2小时，再室温搅拌24小时。将反应后的产物倾入三倍于反应液的甲苯中，离心分离，再用甲苯离心洗涤两次，80℃真空干燥，即得到烷基改性的氧化石墨烯(iGO)。At present, the preparation of modified graphene oxide has a mature process. For example, the preparation process includes: put pre-dried GO (300 mg), octadecyl isocyanate (3.5 g) and 30 ml of dimethylformamide (DMF) in a 100 ml flask, and ultrasonically mix them under nitrogen for 2 hours, and stirred at room temperature for 24 hours. The reacted product was poured into toluene three times as much as the reaction solution, centrifuged, washed twice with toluene, and vacuum-dried at 80°C to obtain alkyl-modified graphene oxide (iGO).
目前，已经有比较成熟的成膜技术制备聚酰亚胺薄膜，整理不再赘述。所制备的聚酰亚胺的合成分子式如下：At present, there are relatively mature film-forming technologies for preparing polyimide films, and the arrangement will not be repeated here. The synthetic molecular formula of prepared polyimide is as follows:
下面通过显示基板的制备过程详细说明本实施例的技术方案。其中，本实施例中所说的“构图工艺”包括沉积膜层、涂覆光刻胶、掩模曝光、显影、刻蚀、剥离光刻胶等处理，其中沉积、涂覆、刻蚀、剥离等均是相关技术中成熟的制备工艺。The technical solution of this embodiment will be described in detail below by showing the preparation process of the substrate. Among them, the "patterning process" mentioned in this embodiment includes deposition of film layer, coating of photoresist, mask exposure, development, etching, stripping of photoresist and other treatments, wherein deposition, coating, etching, stripping etc. are mature preparation techniques in the related art.
本实施例显示基板的制备过程包括：This embodiment shows that the preparation process of the substrate includes:
(1)形成未完全交联的柔性薄膜图案，包括：先在玻璃载板1上涂布聚酰胺酸(polyamide acid，PAA)溶液，然后放置在烘箱中采用130℃～180℃进行固化和热酰胺化，形成厚度为D、交联程度为50％～80％的未完全交联的柔性薄膜10图案，如图2所示。优选地，固化温度为150℃，使柔性薄膜的交联程度为70％。(1) Forming an incompletely cross-linked flexible film pattern, including: first coating a polyamic acid (polyamide acid, PAA) solution on a glass carrier 1, and then placing it in an oven at 130°C to 180°C for curing and heating After amidation, an incompletely crosslinked flexible film 10 pattern with a thickness D and a crosslinking degree of 50% to 80% is formed, as shown in FIG. 2 . Preferably, the curing temperature is 150° C., so that the degree of crosslinking of the flexible film is 70%.
图3为聚酰亚胺在不同固化温度下的XRD图谱。如图3所示，在不同固化温度下，聚酰亚胺的X射线衍射(X-ray diffraction，XRD)图谱表明，当温度低于100℃时，由于温度较低，聚酰亚胺固化交联程度低，其分子之间的层状平行排布结构没有完全形成，因此在20°附近出现馒头状衍射峰。当温度继续增加，衍射峰逐渐尖锐，表明其层状结构逐渐得到完善。当温度升至200°后，XRD曲线基本无变化，说明聚酰亚胺的聚集态结构已保持稳定。本实施例便是利用聚酰亚胺的上述特性，通过控制聚酰亚胺热的固化温度来控制聚酰亚胺薄膜的交联程度。其中，图3种的2θ为晶体衍射方向，晶体衍射方向是指晶体在入射X射线照射下产生的衍射线偏离入射线的角度。XRD是通过对材料进行X射线衍射，分析其衍射图谱，获得材料的成分、材料内部原子或分子的结构或形态等信息的研究手段，用于确定晶体的原子和分子结构。晶体结构导致入射X射线束衍射到许多特定方向，通过测量这些衍射光束的角度和强度，可以产生晶体内电子密度的三维图像，根据该电子密度，可以确定晶体中原子的平均位置，以及它们的化学键和各种其他信息。Figure 3 is the XRD patterns of polyimide at different curing temperatures. As shown in Figure 3, at different curing temperatures, the X-ray diffraction (X-ray diffraction, XRD) pattern of polyimide shows that when the temperature is lower than 100 ° C, due to the lower temperature, the polyimide curing cross The degree of connection is low, and the layered parallel arrangement structure between its molecules is not completely formed, so a bun-like diffraction peak appears around 20°. When the temperature continues to increase, the diffraction peaks gradually become sharper, indicating that the layered structure is gradually perfected. When the temperature rises to 200°, the XRD curve basically does not change, indicating that the aggregated structure of polyimide has remained stable. In this embodiment, the above-mentioned characteristics of polyimide are used to control the degree of crosslinking of the polyimide film by controlling the curing temperature of the polyimide heat. Among them, 2θ in Fig. 3 is the direction of crystal diffraction, and the direction of crystal diffraction refers to the angle at which the diffraction line generated by the crystal under the irradiation of incident X-rays deviates from the incident line. XRD is a research method for obtaining information such as the composition of materials, the structure or morphology of atoms or molecules inside materials, and is used to determine the atomic and molecular structures of crystals by performing X-ray diffraction on materials and analyzing their diffraction patterns. The crystal structure causes the incident X-ray beam to diffract into many specific directions. By measuring the angle and intensity of these diffracted beams, a three-dimensional image of the electron density within the crystal can be produced. From this electron density, the average position of the atoms in the crystal can be determined, as well as their Chemical bonds and various other information.
(2)形成光刻胶图案，包括：在形成上述结构的基础上，涂覆一层光刻胶，然后采用掩膜板进行曝光，通过显影形成光刻胶100图案，如图4所示。其中，光刻胶可以采用正性光刻胶，也可以采用负性光刻胶。实际实施时，本次工艺采用的掩膜板和后续制备有源层的掩膜板可以采用同一个掩膜板(Mask)，以降低制备成本。优选地，本实施例采用负性光刻胶，通过控制曝光量，使光刻胶去除区域的长度大于后续制备的有源层的实际长度。(2) Forming a photoresist pattern, including: coating a layer of photoresist on the basis of forming the above structure, then exposing with a mask plate, and forming a photoresist 100 pattern by developing, as shown in FIG. 4 . Wherein, the photoresist can be a positive photoresist or a negative photoresist. In actual implementation, the same mask (Mask) may be used for the mask used in this process and for the subsequent preparation of the active layer, so as to reduce the manufacturing cost. Preferably, in this embodiment, a negative photoresist is used, and the length of the photoresist removed region is greater than the actual length of the subsequently prepared active layer by controlling the exposure amount.
(3)刻蚀柔性薄膜10，包括：采用干刻方式刻蚀未被光刻胶100图案覆盖的柔性薄膜10，剥离光刻胶100后，在柔性薄膜10上形成凹槽10a，如图5所示。其中，干刻可以采用等离子体干法刻蚀工艺，凹槽10a的深度d＝30％D～50％D。(3) Etching the flexible film 10 includes: etching the flexible film 10 not covered by the pattern of the photoresist 100 by dry etching, and forming a groove 10a on the flexible film 10 after peeling off the photoresist 100, as shown in Figure 5 shown. Wherein, the dry etching may adopt a plasma dry etching process, and the depth d of the groove 10a is 30%D˜50%D.
(4)形成未完全交联的GO/PI复合薄膜或iGO/PI复合薄膜，包括：在形成上述结构的基础上，涂覆GO/PAA溶液，通过加热固化、热酰胺化等处理，形成厚度大于d、交联程度为50％～80％的未完全交联的氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺(iGO/PI)复合薄膜20，且GO/PI复合薄膜或iGO/PI复合薄膜完全填充凹槽10a，如图6所示。其中，氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜中，氧化石墨烯GO的质量分数是3％～7％，改性氧化石墨烯/聚酰亚胺(iGO/PI)复合薄膜中，改性氧化石墨烯iGO的质量分数是0.5％～1.5％，固化温度为130℃～180℃。优选地，氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜中，氧化石墨烯GO的质量分数是5％，改性氧化石墨烯/聚酰亚胺(iGO/PI)复合薄膜中，改性氧化石墨烯iGO的质量分数是1.0％，固化温度为150℃，使GO/PI复合薄膜或iGO/PI复合薄膜的交联程度为70％。(4) Forming an incompletely cross-linked GO/PI composite film or iGO/PI composite film, including: on the basis of forming the above structure, coating GO/PAA solution, heat curing, heat amidation, etc., to form a thick Incompletely crosslinked graphene oxide/polyimide (GO/PI) composite film or incompletely crosslinked modified graphene oxide/polyimide ( iGO/PI) composite film 20, and the GO/PI composite film or iGO/PI composite film completely fills the groove 10a, as shown in FIG. 6 . Among them, in the graphene oxide/polyimide (GO/PI) composite film, the mass fraction of graphene oxide GO is 3% to 7%, and the modified graphene oxide/polyimide (iGO/PI) composite film Among them, the mass fraction of the modified graphene oxide iGO is 0.5%-1.5%, and the curing temperature is 130°C-180°C. Preferably, in the graphene oxide/polyimide (GO/PI) composite film, the mass fraction of graphene oxide GO is 5%, in the modified graphene oxide/polyimide (iGO/PI) composite film, The mass fraction of modified graphene oxide iGO is 1.0%, and the curing temperature is 150°C, so that the crosslinking degree of GO/PI composite film or iGO/PI composite film is 70%.
其中，GO/PAA溶液的制备可以采用前述介绍的现有成熟的工艺参数。例如，制备GO/PAA溶液或iGO/PAA溶液时，称取一定量干燥后的GO或iGO溶于DMAc中，超声2小时得到GO或iGO的DMAc溶液。将一定比例的GO或iGO的DMAc溶液与固含量为15wt％的PAA溶液及DMAc溶剂混合搅拌4小时后，得到GO/PAA溶液或iGO/PAA溶液。Among them, the preparation of GO/PAA solution can adopt the existing mature process parameters introduced above. For example, when preparing GO/PAA solution or iGO/PAA solution, a certain amount of dried GO or iGO was weighed and dissolved in DMAc, and the DMAc solution of GO or iGO was obtained by ultrasonication for 2 hours. GO/PAA solution or iGO/PAA solution was obtained after mixing a certain proportion of GO or iGO DMAc solution with 15wt% solid content of PAA solution and DMAc solvent and stirring for 4 hours.
(5)研磨GO/PI复合薄膜或iGO/PI复合薄膜，包括：采用化学机械平坦化(ChemicalMechanical Planarization，CMP)工艺进行研磨，将柔性薄膜10表面上的GO/PI复合薄膜或iGO/PI复合薄膜全部去除，只保留凹槽10a中的GO/PI复合薄膜或iGO/PI复合薄膜，形成嵌设在柔性薄膜开设的凹槽内的GO/PI复合薄膜或者是iGO/PI复合薄膜20图案，如图7所示。(5) Grinding GO/PI composite film or iGO/PI composite film, including: using chemical mechanical planarization (ChemicalMechanical Planarization, CMP) process for grinding, the GO/PI composite film or iGO/PI composite film on the surface of the flexible film 10 All the films are removed, and only the GO/PI composite film or iGO/PI composite film in the groove 10a is retained to form a pattern of GO/PI composite film or iGO/PI composite film 20 embedded in the groove opened by the flexible film, As shown in Figure 7.
(6)完全交联处理，包括：将经过上述工艺完成的结构置于高温烘箱中，在200℃～350℃下恒温处理1.5小时～2.5小时，进行二次固化，使未完全交联的柔性薄膜10、未完全交联的GO/PI复合薄膜或iGO/PI复合薄膜20完全交联。同时，二次固化过程也会使柔性薄膜10与GO/PI复合薄膜或iGO/PI复合薄膜20的接触边界处发生交联反应，从而使凹槽中的GO/PI复合薄膜或iGO/PI复合薄膜20与柔性薄膜10融为一体，形成嵌设有GO/PI复合薄膜或iGO/PI复合薄膜20的柔性基底10。优选地，恒温处理的温度为300℃，恒温处理的时间为2小时。(6) Complete cross-linking treatment, including: placing the structure completed by the above process in a high-temperature oven, and treating it at a constant temperature at 200 ° C to 350 ° C for 1.5 hours to 2.5 hours, and performing secondary curing to make the incompletely cross-linked flexible Film 10, incompletely cross-linked GO/PI composite film or iGO/PI composite film 20 is completely cross-linked. At the same time, the secondary curing process will also cause a crosslinking reaction at the contact boundary between the flexible film 10 and the GO/PI composite film or iGO/PI composite film 20, so that the GO/PI composite film or iGO/PI composite film in the groove The film 20 is integrated with the flexible film 10 to form a flexible substrate 10 embedded with the GO/PI composite film or iGO/PI composite film 20 . Preferably, the temperature of the constant temperature treatment is 300° C., and the time of the constant temperature treatment is 2 hours.
(7)制备包括薄膜晶体管的阵列结构层。本实施例制备包括薄膜晶体管的阵列结构层的过程与相关制备工艺相同，包括：依次沉积缓冲薄膜和有源层薄膜，通过构图工艺形成缓冲层11和设置在缓冲层11上的有源层12。依次沉积第一绝缘薄膜和第一金属薄膜，通过构图工艺形成覆盖有源层12的第一绝缘层13和设置在第一绝缘层13上的栅电极14。沉积第二绝缘薄膜，通过构图工艺形成覆盖栅电极14的第二绝缘层15，其上开设有暴露出有源层12的两个第一过孔。沉积第二金属薄膜，通过构图工艺在第二绝缘层15上形成源电极16和漏电极17，源电极16和漏电极17分别通过第二绝缘层15上开设的两个第一过孔与有源层12连接。沉积第三绝缘薄膜，通过构图工艺形成覆盖源电极16和漏电极17的第三绝缘层18，其上开设有暴露出漏电极17的第二过孔，如图8所示。当然，对于OLED显示基板，后续还包括形成阳极、有机发光层、阴极和封装层等工艺，为本领域公知技术，这里不再赘述。(7) Prepare an array structure layer including thin film transistors. In this embodiment, the process of preparing an array structure layer including thin film transistors is the same as the related preparation process, including: sequentially depositing a buffer film and an active layer film, and forming a buffer layer 11 and an active layer 12 disposed on the buffer layer 11 through a patterning process . A first insulating film and a first metal film are deposited in sequence, and a first insulating layer 13 covering the active layer 12 and a gate electrode 14 disposed on the first insulating layer 13 are formed through a patterning process. A second insulating film is deposited, and a second insulating layer 15 covering the gate electrode 14 is formed by a patterning process, and two first via holes exposing the active layer 12 are opened thereon. The second metal thin film is deposited, and the source electrode 16 and the drain electrode 17 are formed on the second insulating layer 15 through a patterning process, and the source electrode 16 and the drain electrode 17 respectively pass through the two first via holes opened on the second insulating layer 15 and have The source layer 12 is connected. A third insulating film is deposited, and a third insulating layer 18 covering the source electrode 16 and the drain electrode 17 is formed by a patterning process, on which a second via hole exposing the drain electrode 17 is opened, as shown in FIG. 8 . Of course, for the OLED display substrate, subsequent processes including forming the anode, the organic light-emitting layer, the cathode, and the encapsulation layer are well-known technologies in the art and will not be repeated here.
最后，剥离玻璃载板1，形成本实施例显示基板，如图1所示。Finally, the glass carrier 1 is peeled off to form the display substrate of this embodiment, as shown in FIG. 1 .
这样，经过前述工艺流程，即制备完成嵌设有GO/PI复合薄膜或iGO/PI复合薄膜的柔性基底，以及形成在柔性基底上的阵列结构层。由于嵌设的GO/PI复合薄膜或iGO/PI复合薄膜的弹性模量相对于周边的聚酰亚胺PI的弹性模量具有较大幅度的提升，从而增强了该区域的抗形变能力。由于GO/PI复合薄膜或iGO/PI复合薄膜的位置与薄膜晶体管沟道区的位置相对应，因而相应提高了薄膜晶体管沟道区的抗形变能力，能够在显示基板弯曲时减小甚至消除薄膜晶体管沟道区的变形，避免因薄膜晶体管沟道区形变过大影响薄膜晶体管的电性参数，保证发光稳定性，提升显示品质，有效解决了现有显示装置存在发光不稳定的问题。In this way, the flexible substrate embedded with the GO/PI composite thin film or the iGO/PI composite thin film and the array structure layer formed on the flexible substrate are prepared through the aforementioned process flow. Since the elastic modulus of the embedded GO/PI composite film or iGO/PI composite film is greatly improved compared with that of the surrounding polyimide PI, the deformation resistance of this region is enhanced. Since the position of the GO/PI composite film or iGO/PI composite film corresponds to the position of the channel region of the thin film transistor, the deformation resistance of the channel region of the thin film transistor is correspondingly improved, and the thin film can be reduced or even eliminated when the display substrate is bent. The deformation of the channel region of the transistor avoids the influence of the electrical parameters of the thin film transistor due to excessive deformation of the channel region of the thin film transistor, ensures the stability of light emission, improves the display quality, and effectively solves the problem of unstable light emission in existing display devices.
进一步地，本实施例通过二次交联固化，使凹槽内的GO/PI复合薄膜或iGO/PI复合薄膜与周边的聚酰亚胺PI完全全部交联且融为一体，保证了整个柔性基底的弯曲性能，在不影响聚酰亚胺柔性基底整体弯曲性能的基础上，实现了薄膜晶体管沟道区抗形变能力的提高，起到了较好的防护性能。Further, in this embodiment, the GO/PI composite film or iGO/PI composite film in the groove is completely cross-linked and integrated with the surrounding polyimide PI through secondary cross-linking and curing, ensuring the overall flexibility. The bending performance of the substrate, on the basis of not affecting the overall bending performance of the polyimide flexible substrate, realizes the improvement of the deformation resistance of the channel region of the thin film transistor, and plays a better protective performance.
进一步地，由于本实施例制备凹槽时采用负性光刻胶，且通过控制曝光量，使凹槽内GO/PI复合薄膜或iGO/PI复合薄膜的长度大于有源层的长度，即GO/PI复合薄膜或iGO/PI复合薄膜在基底上的正投影包含有源层在柔性基底上的正投影。本实施例中，A正投影包含B正投影是指A在基底上正投影的边界位于B在基底上正投影的边界之外。这样，本实施例所设置的GO/PI复合薄膜或iGO/PI复合薄膜就能充分的保护有源层，充分保护薄膜晶体管的沟道区。Further, since this embodiment uses a negative photoresist to prepare the groove, and by controlling the amount of exposure, the length of the GO/PI composite film or iGO/PI composite film in the groove is greater than the length of the active layer, that is, the GO The orthographic projection of the /PI composite thin film or the iGO/PI composite thin film on the substrate includes the orthographic projection of the active layer on the flexible substrate. In this embodiment, the orthographic projection of A includes the orthographic projection of B, which means that the boundary of the orthographic projection of A on the base is outside the boundary of the orthographic projection of B on the base. In this way, the GO/PI composite thin film or iGO/PI composite thin film provided in this embodiment can fully protect the active layer and the channel region of the thin film transistor.
需要说明的是，本实施例所示的制备过程仅仅是一种示例性说明。实际实施时，可以根据实际需要变更制备工艺。例如，上述通过涂覆光刻胶形成凹槽的工艺可以进行简化，先在玻璃载板1制备出厚度为D、且具有负性光敏性的柔性薄膜，柔性薄膜的交联程度为50％～80％。然后采用掩膜板进行曝光、显影，形成深度为d的凹槽，其中显影为不完全显影，即显影后柔性薄膜被部分显影去除，同时控制曝光量，使凹槽的长度大于后续制备的有源层的长度。同样，本实施例所示的显示基板结构仅仅是一种示例性说明，本实施例显示基板中的薄膜晶体管不仅可以是顶栅结构，也可以是底栅结构，薄膜晶体管可以是非晶硅(a-Si)薄膜晶体管、低温多晶硅(LTPS)薄膜晶体管或氧化物(Oxide)薄膜晶体管，阵列结构层中还可以设置其它电极、引线和结构膜层，本发明实施例在此不做具体的限定。It should be noted that the preparation process shown in this embodiment is only an exemplary description. During actual implementation, the preparation process can be changed according to actual needs. For example, the above-mentioned process of forming grooves by coating photoresist can be simplified. First, a flexible film with thickness D and negative photosensitive properties is prepared on the glass carrier 1, and the crosslinking degree of the flexible film is 50% to 50%. 80%. Then, a mask plate is used for exposure and development to form a groove with a depth of d, wherein the development is incomplete development, that is, the flexible film is partially developed and removed after development, and the exposure amount is controlled at the same time so that the length of the groove is greater than that of the subsequent preparation. The length of the source layer. Likewise, the structure of the display substrate shown in this embodiment is only an exemplary illustration. The thin-film transistors in the display substrate of this embodiment may not only have a top-gate structure, but also a bottom-gate structure, and the thin-film transistors may be amorphous silicon (a -Si) thin film transistors, low temperature polysilicon (LTPS) thin film transistors or oxide (Oxide) thin film transistors, other electrodes, leads and structural film layers can also be arranged in the array structure layer, which is not specifically limited in this embodiment of the present invention.
第二实施例second embodiment
基于本发明的技术构思，本发明实施例还提供了一种显示基板的制备方法。本发明实施例显示基板的制备方法包括：Based on the technical concept of the present invention, the embodiment of the present invention also provides a method for preparing a display substrate. The embodiment of the present invention shows that the preparation method of the substrate includes:
S1、形成嵌设有强化层的柔性基底；S1, forming a flexible substrate embedded with a strengthening layer;
S2、在所述柔性基底上形成薄膜晶体管，使所述强化层的位置与薄膜晶体管沟道区的位置相对应，以提高薄膜晶体管沟道区的抗形变能力。S2. Forming a thin film transistor on the flexible substrate, so that the position of the strengthening layer corresponds to the position of the channel region of the thin film transistor, so as to improve the deformation resistance of the channel region of the thin film transistor.
其中，步骤S1包括：Wherein, step S1 includes:
S11、在玻璃载板上形成未完全交联的柔性薄膜；S11, forming an incompletely cross-linked flexible film on the glass carrier;
S12、在所述未完全交联的柔性薄膜上开设凹槽，所述凹槽的深度为所述未完全交联的柔性薄膜厚度的30％～50％；S12. Opening grooves on the incompletely crosslinked flexible film, the depth of the grooves being 30% to 50% of the thickness of the incompletely crosslinked flexible film;
S13、在所述凹槽内形成未完全交联的强化薄膜，所述未完全交联的强化薄膜的表面与所述未完全交联的柔性薄膜的表面平齐；S13, forming an incompletely crosslinked reinforced film in the groove, the surface of the incompletely crosslinked reinforced film is flush with the surface of the incompletely crosslinked flexible film;
S14、通过固化处理，使所述未完全交联的柔性薄膜和未完全交联的强化薄膜完全交联，形成嵌设有强化层的柔性基底，且强化层与柔性基底融为一体。S14. Through curing treatment, the incompletely crosslinked flexible film and the incompletely crosslinked reinforcement film are completely crosslinked to form a flexible substrate embedded with a reinforcement layer, and the reinforcement layer is integrated with the flexible substrate.
其中，所述未完全交联的柔性薄膜包括交联程度为50％-80％的聚酰亚胺薄膜，所述未完全交联的强化薄膜包括交联程度为50％-80％的氧化石墨烯/聚酰亚胺复合薄膜或交联程度为50％-80％的改性氧化石墨烯/聚酰亚胺复合薄膜。Wherein, the incompletely cross-linked flexible film includes a polyimide film with a cross-linking degree of 50%-80%, and the incompletely cross-linked reinforced film includes a graphite oxide film with a cross-linking degree of 50%-80%. olefin/polyimide composite film or modified graphene oxide/polyimide composite film with a crosslinking degree of 50%-80%.
其中，所述氧化石墨烯/聚酰亚胺复合薄膜中，所述氧化石墨烯的质量分数为3％～7％；所述改性氧化石墨烯/聚酰亚胺复合薄膜中，所述改性氧化石墨烯的质量分数为0.5％～1.5％。Wherein, in the graphene oxide/polyimide composite film, the mass fraction of the graphene oxide is 3% to 7%; in the modified graphene oxide/polyimide composite film, the modified The mass fraction of graphene oxide is 0.5%-1.5%.
其中，步骤S14中的固化处理包括：在200℃～350℃高温烘箱中恒温处理1.5小时～2.5小时。Wherein, the curing treatment in step S14 includes: constant temperature treatment in a high-temperature oven at 200° C. to 350° C. for 1.5 hours to 2.5 hours.
其中，步骤S12包括：在所述未完全交联的柔性薄膜上涂覆一层负性光刻胶，通过曝光、显影形成负性光刻胶图案，采用干刻方式刻蚀未被负性光刻胶图案覆盖的所述未完全交联的柔性薄膜，在所述未完全交联的柔性薄膜上形成凹槽，所述凹槽的深度为所述未完全交联的柔性薄膜厚度的30％～50％。Wherein, step S12 includes: coating a layer of negative photoresist on the incompletely cross-linked flexible film, forming a negative photoresist pattern through exposure and development, and etching the non-negative photoresist pattern by dry etching. The incompletely crosslinked flexible film covered by the resist pattern forms a groove on the incompletely crosslinked flexible film, and the depth of the groove is 30% of the thickness of the incompletely crosslinked flexible film ~50%.
其中，步骤S13包括：涂覆氧化石墨烯/聚酰胺酸溶液或改性氧化石墨烯/聚酰胺酸溶液，形成未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜，所述未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜完全填充所述凹槽；采用化学机械平坦化工艺进行研磨，只保留所述凹槽中的未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜，在所述凹槽内形成未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜，所述未完全交联的氧化石墨烯/聚酰亚胺复合薄膜或未完全交联的改性氧化石墨烯/聚酰亚胺复合薄膜的表面与所述未完全交联的柔性薄膜的表面平齐。Wherein, step S13 includes: coating graphene oxide/polyamic acid solution or modified graphene oxide/polyamic acid solution to form incompletely crosslinked graphene oxide/polyimide composite film or incompletely crosslinked Modified graphene oxide/polyimide composite film, the incompletely crosslinked graphene oxide/polyimide composite film or the incompletely crosslinked modified graphene oxide/polyimide composite film is completely filled The groove; the chemical mechanical planarization process is used for grinding, and only the incompletely crosslinked graphene oxide/polyimide composite film or the incompletely crosslinked modified graphene oxide/polyimide composite film in the groove is kept. An imide composite film, forming an incompletely crosslinked graphene oxide/polyimide composite film or an incompletely crosslinked modified graphene oxide/polyimide composite film in the groove, the non-completely crosslinked graphene oxide/polyimide composite film The surface of the fully crosslinked graphene oxide/polyimide composite film or the incompletely crosslinked modified graphene oxide/polyimide composite film is flush with the surface of the incompletely crosslinked flexible film.
其中，所述强化层在所述柔性基底上的正投影包含所述薄膜晶体管的有源层在所述柔性基底上的正投影。Wherein, the orthographic projection of the strengthening layer on the flexible substrate includes the orthographic projection of the active layer of the thin film transistor on the flexible substrate.
其中，步骤S2中在所述柔性基底上形成薄膜晶体管，包括：在所述柔性基底上形成低温多晶硅薄膜晶体管。Wherein, forming a thin film transistor on the flexible substrate in step S2 includes: forming a low temperature polysilicon thin film transistor on the flexible substrate.
有关显示基板的具体制备过程已在前述第一实施例中详细说明，这里不再赘述。The specific preparation process of the display substrate has been described in detail in the foregoing first embodiment, and will not be repeated here.
本实施例提供了一种显示基板的制备方法，通过在基底上嵌设强化层，强化层与薄膜晶体管沟道区的位置相对应，提高了薄膜晶体管沟道区的抗形变能力，在显示基板弯曲时能够减小甚至消除薄膜晶体管沟道区的形变，避免因薄膜晶体管沟道区形变过大影响薄膜晶体管的电性参数，保证了发光稳定性，提升了显示品质，有效解决了现有显示装置存在的发光不稳定的问题。此外，本实施例显示基板的制备方法利用现有成熟的制备设备即可实现，对现有工艺改进较小，能够很好地与现有制备工艺兼容，具有工艺简单、易于实现和生产成本低等优点，具有良好的应用前景。This embodiment provides a method for preparing a display substrate. By embedding a strengthening layer on the substrate, the strengthening layer corresponds to the position of the channel region of the thin film transistor, thereby improving the deformation resistance of the channel region of the thin film transistor. When bending, it can reduce or even eliminate the deformation of the channel region of the thin film transistor, avoid the influence of the electrical parameters of the thin film transistor due to excessive deformation of the channel region of the thin film transistor, ensure the stability of light emission, improve the display quality, and effectively solve the problem of existing display problems. The device has the problem of unstable luminescence. In addition, this example shows that the preparation method of the substrate can be realized by using the existing mature preparation equipment, the improvement of the existing process is small, it can be well compatible with the existing preparation process, and it has the advantages of simple process, easy implementation and low production cost And other advantages, has a good application prospect.
第三实施例third embodiment
本发明实施例还提供了一种显示装置，显示装置包括前述实施例的显示基板。显示装置可以为：手机、平板电脑、电视机、显示器、笔记本电脑、数码相框、导航仪等任何具有显示功能的产品或部件。An embodiment of the present invention also provides a display device, which includes the display substrate of the foregoing embodiment. The display device can be any product or component with a display function such as a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital photo frame, a navigator, and the like.
在本发明实施例的描述中，需要理解的是，术语“中部”、“上”、“下”、“前”、“后”、“竖直”、“水平”、“顶”、“底”“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。In the description of the embodiments of the present invention, it should be understood that the terms "middle", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom" The orientation or positional relationship indicated by "inside", "outside" and so on is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must Having a particular orientation, being constructed and operating in a particular orientation, and therefore not to be construed as limiting the invention.
在本发明实施例的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以具体情况理解上述术语在本发明中的具体含义。In the description of the embodiments of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a A detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediary, and it may be an internal communication between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.
虽然本发明所揭露的实施方式如上，但所述的内容仅为便于理解本发明而采用的实施方式，并非用以限定本发明。任何本发明所属领域内的技术人员，在不脱离本发明所揭露的精神和范围的前提下，可以在实施的形式及细节上进行任何的修改与变化，但本发明的专利保护范围，仍须以所附的权利要求书所界定的范围为准。Although the embodiments disclosed in the present invention are as above, the described content is only an embodiment adopted for understanding the present invention, and is not intended to limit the present invention. Anyone skilled in the field of the present invention can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention, but the patent protection scope of the present invention must still be The scope defined by the appended claims shall prevail.
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910596302.2ACN110299369B (en) | 2019-07-03 | 2019-07-03 | Display substrate, preparation method thereof and display device |
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| CN201910596302.2ACN110299369B (en) | 2019-07-03 | 2019-07-03 | Display substrate, preparation method thereof and display device |
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| CN110299369Atrue CN110299369A (en) | 2019-10-01 |
| CN110299369B CN110299369B (en) | 2021-11-16 |
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| CN201910596302.2AExpired - Fee RelatedCN110299369B (en) | 2019-07-03 | 2019-07-03 | Display substrate, preparation method thereof and display device |
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